In recent years, various electrical equipments have been mounted on an automobile, and many fuses for protecting various electronic devices, used in electric circuits of the electrical equipments, are received in a fuse box or the like.
A conventional fusible link 1, shown in FIGS. 7 and 8, is a so-called plug-in type fuse, and comprises a fuse body 2 made of a metal sheet, a housing 3 which is made of an insulative resin, and has the fuse body 2 received and held therein (the fuse body 2 is inserted into the housing 3 through an upper opening of a rectangular shape in the housing 3), and a cover 4 which is made of an insulative resin, and covers the upper opening in the housing 3.
As shown in FIG. 8, the fuse body 2 includes a strip-like fusible conductor portion 10 having a melting portion 10a, and a pair of female terminal portions 11 and 11 which are formed respectively at both ends of the fusible conductor portion 10, and can be fittingly connected respectively to mating tab terminals 15 formed on a circuit provided at a fuse mounting portion 13. This fuse body 2 is formed into an integral construction, using a metal sheet.
The cover 4 includes a lid 5 in the form of a generally rectangular plate, and a pair of lock piece portions 6 and 6 extending downwardly respectively from opposite end edges of the lid 5, and this cover 4 is molded into an integral construction, using a transparent plastics material. Retaining projections 7 are formed on and project respectively from those portions of a peripheral wall of the housing 3 corresponding respectively to the lock piece portions 6. When the pair of elastic lock piece portions 6 and 6 are retainingly engaged with the retaining projections 7, respectively, the cover 4 is locked to the housing 3 in such a manner that this cover 4 covers the upper opening in the housing 3.
The fusible link 1 is mounted in the fuse mounting portion 13 formed at an electric connection box such as a fuse box, and the fuse body 2 is electrically connected to the mating tab terminals 15. A fuse guide wall 14 for supporting the housing 3 is formed at the fuse mounting portion 13, and this fuse guide wall 14 serves to guide the insertion of the fusible link 1 at the time of mounting the fusible link, and also serves to prevent the fusible link 1 from being displaced out of position after the fusible link is mounted.
Electric connection boxes such as a fuse box have increasingly been required to have a compact and lightweight design and a cost-reduced design, and in this connection fuses also have been required to have a compact and lightweight design.
Therefore, for example, when a fuse body 22 as well as a housing 23 is formed into a compact design as in a fusible link 21 shown in FIG. 9, this fusible link can be much more reduced in size and weight to have a reduced height as compared with the conventional fusible link 1 shown in FIG. 7. As a result, the compact and lightweight design of the electric connection box is achieved.
In the fuse body 22, secondary short-circuiting or the like must be prevented when a fusible conductor portion 28 melts, and therefore it is difficult to further reduce the distance between a pair of female terminal portions 29 and 29.
Therefore, horizontal dimensions and shapes of the fuse body 22 and housing 23 are substantially the same as those of the fuse body 2 and housing 3 of the fusible link 1, and a cover 24 has the same shape as that of the cover 4, and the cover 24 is locked to the housing 23 by lock piece portions 26 retainingly engaged respectively with retaining projections 27 formed on and projecting from a peripheral wall of the housing 23.
JP-A-2001-325875, mentioned below, discloses a plug-in type fuse body which is inserted into a housing of an insulative resin through an upper opening thereof, and is received and held therein. In this plug-in type fuse, spring properties of holder springs of two female terminal portions are enhanced, and besides a resistance is reduced so that this fuse can meet a high rating.
JP-A-8-185797, mentioned below, discloses a fusible link in which a cover of a transparent plastics material, having a rated current value indicated thereon, is fitted on an upper opening portion of a housing, and a recess or a projection which can be detected by a sensor is provided at an inner surface of the cover at a position different depending on the rated current value.
However, in the above conventional fusible links comprising the cover, the housing, and the fuse body, any retaining portion, corresponding to a retaining portion of a withdrawing jig, is not provided at a side surface of the housing, and therefore when withdrawing the housing, the jig is liable to be disengaged from the housing, and therefore a relatively large force is required for this withdrawing operation, and therefore there has been encountered a problem that the efficiency of the withdrawing operation is low.
Another problem is that there is a fear that the housing is damaged when a large force for withdrawing purposes is applied to the side surface of the housing.